of just one analog broadcast. Any program services, not necessarily from the same broadcaster, can be interleaved on the same transport. Programming from a commercial broadcaster that would not otherwise be available in the station's broadcast area can be transmitted. Digital television transports vary in the number of channels that can be transmitted, based on the bandwidth of the multiplex and the broadcast quality specified for each channel. Digital terrestrial offers the least, digital cable and satellite the most bandwidth. A single transport may carry conventional television channels, radio, teletext, and sometimes hidden channels carrying metadata or interactive services. United States In the United States, the standard for over-the-air digital transmissions is ATSC, digital cable is based on the worldwide DVB standard, DVB-C ("C" for cable) and transmission via satellite are based on the DVB-S ("S" for satellite) standard, all use multiplexes to deliver various channels to the viewer. Smaller and newer commercial networks, such as The CW and MyNetworkTV, are available in some markets as digital subchannels of stations affiliated with other networks rather than as standalone stations. A transport can also carry radio and interactive television content. A typical American ATSC transport offers three to four channels; in most cases one of them is broadcast in HD (the station's main channel) and the rest of the channels are broadcast in standard definition, due to the limited 6 MHz 8VSB bandwidth used. In those cases when one physical channel transports more than one HD sub-channel, the data rate drops to the level of standard definition DVD-Video. The corresponding image degradation manifests itself in reduced resolution, increased noise and compression artifacts. For example, KPBS broadcasts four multiplexes on a single physical channel, two of which are HD. Europe In Europe, transports are used on CODFM 64-QAM/256-QAM modulated DVB-T and DVB-T2 ("T" for terrestrial) digital terrestrial standards, on CODFM 256-QAM modulated DVB-C digital cable and on CODFM QPSK/8PSK modulated DVB-S digital satellite. Publicly and privately owned television broadcasters use interleaving to broadcast many digital channels over a few transports using the various digital broadcast standards. A typical DVB-T transport in Europe offers four or more standard definition channels transmitted simultaneously; if some channels transmit only for part of the day (for example, a children's channel during daytime, a channel with programs for adults in the evening), many channels may share the same transport. External links Technical list of UK multiplexes Digital